October 1 - Sun

A male dance fly (Empis livida), of the familyEmpididae, a family of flies with over 3,000 described species. Empidids are mainly predatory flies and exhibit a wide range of forms but are generally small to medium sized, non-metallic and rather bristly. Distribution is worldwide but the majority are found in northern temperate areas.

October 3 - Tue

This map shows the tracks of all tropical cyclones which formed worldwide from 1985 to 2005. The points show the locations of the storms at six-hourly intervals and use the color scheme shown on the right from the Saffir-Simpson Hurricane Scale.

October 6 - Fri

Sixth century mural from the wall of the Ajanta Caves, Maharashtra, India, painted during the Gupta Empire. These paintings, like many produced in this time period, freely depict nudity, romantic themes or sexual situations, reflecting the lack of taboos against sex in a society that also produced the Kama Sutra and the Tantric school of Indian philosophy.

October 7 - Sat

A sculler rowing in front of the European Parliament building in Strasbourg, France. Although Brussels is usually considered the 'capital' of the European Union, the Parliament meets monthly in Strasbourg. The rival demands of Belgium and France to base parliament in their state has prevented a final agreement as to which city would become the sole seat of parliament.

October 10 - Tue

Three willow flowers appearing as catkins. Willows are deciduoustrees and shrubs in the genus Salix, part of the willow family Salicaceae. Willows are dioecious with male and female catkins on different plants; the catkins are produced early in the spring, often before the leaves or as the new leaves open.

October 13 - Fri

The central electrode of a plasma lamp, showing a glowing blue plasma streaming upwards. The colors are a result of the radiative recombination of electrons and ions and the relaxation of electrons in excited states back to lower energy states. These processes emit light in a spectrum characteristic of the gas being excited.

October 16 - Mon

This animation shows the changing views of spacetime along the world line (the dashed line) of a rapidly accelerating observer under the special theory of relativity, proposed by Albert Einstein in 1905. The vertical direction indicates time and the horizontal direction indicates distance, and the dots on the world line are spaced at regular proper time intervals. The diagonal lines show the particle's light cone at that time. The other dots are random events.

October 17 - Tue

Carts have many different shapes but the basic idea of transporting material (or maintaining a collection of materials in a portable fashion) remains. Carts usually have two or four wheels. Those with four wheels (also known as drays or wagons) will often have a pivoting front axle that has a pole connected to the collars or yoke of the two guiding draught animals.

October 18 - Wed

A domesticated Swan Goose (Anser cygnoides) with a "knob" (found in some variations) above its beak. This knob is more prominent on males than on females and can be used for sexing by 6–8 weeks of age. Wild Swan Geese can be found in Mongolia and eastern Russia. They are migratory and winter mostly in south and east China.

October 20 - Fri

Pangong Tso is a lake in the Himalayas situated at a height of about 4500 m (14850 ft). It is 134 km long and extends from India to Tibet. Two thirds of the length of this lake falls in the People's Republic of China. It is only 8 km wide at its broadest point. In winter, the lake freezes completely despite being salt water.

October 21 - Sat

Apa Tani tribal women, with traditional tattoos and bamboo nose ornaments in Hija village, Ziro, Arunachal Pradesh, India. Originally, this practice started because the women wanted to look unattractive to males from other tribes. Apa Tani women were considered to be the most beautiful among all the Arunachal tribes.

October 23 - Mon

In this example of isometric projection, the blue sphere is two levels above the red one, but this can't be seen locally. If the pier that the blue sphere is on were extended by one square, it would align perfectly with the square the red sphere is on, creating an optical illusion. Some of the famous "impossible architecture" works of M.C. Escher exploit this isometric limitation.

October 26 - Thu

Symmetry is a foundational concept in several sub-disciplines of mathematics, particularly geometry and abstract algebra. The rotation symmetry group of the tetrahedron (shown here) associates the 12 different orientations of a tetrahedron with two kinds of spatial rotation that rearrange those orientations: a 120° rotation around each of the 4 vertices (reddish arrows), and 180° rotation through opposite edges (blue arrows). Diagrams illustrating the symmetries of a mathematical object in this format are called cycle graphs.

October 27 - Fri

Flowers of the cultivarHebe × franciscana, commonly known as "Blue Gem" or "Veronica", a member of the Hebegenus. This hybrid has been known to be continuously in flower for stretches over two years. Hebes are grown in many gardens and public areas as they attract butterflies. They cope with most soil types, and can be propagated easily from both seed and cuttings.

October 28 - Sat

Composite photo of the Sun and Earth, showing the difference in size between the two astronomical objects. Although the Sun is an average-sized star, it is so large that its volume is equivalent to 1.3 million Earths and it contains approximately 99% of the total mass of the solar system.

October 29 - Sun

Animation of a drop of water falling from a tap. While still connected to the tap, surface tension counters the gravitational pull until the drop becomes too large and heavy to be supported. This animation is made of 18 separate images, not all of the same water drop, but different pictures of different drops arranged to make them look like a series of pictures of one drop.

October 30 - Mon

A Canada Goose in flight. This well-known species is native to North America. It breeds in Canada and the northern USA in a variety of habitats. Like most geese, it is naturally migratory, the wintering range being most of the USA.